反应详情

4-Amino-3-hydroxybenzoic acid is converted into 1,3-benzoxazol-5-carboxylic acid by treating with diethoxymethyl acetate as described for the preparation of Invention Compound IX. EMIS m/z=163 (parent), 146 (base), 118, 90, and 63. Coupling of the acid with 1,2,3,6-tetrahydropyridine is performed in the same manner as described for the preparation of isomeric Invention Compound IX. 1H NMR δ 2.1-2.4 (br, 4), 3.4-4.3 (br m, 4), 5.5-5.95 (br m, 2), 7.45 (dd, 1, J=8.17, 1.41 Hz), 7.70 (d, 1, J=0.96 Hz), 7.83 (d, 1, J=8.16 Hz), and 8.18 ppm (s, 1).